1. Field of the Invention
The present invention relates to a method and apparatus for sheet finishing, and more particularly to a method and apparatus for sheet finishing which is capable of performing an effective jogging process.
2. Description of the Related Art
A sheet finishing apparatus is typically connected to or integral with an image forming apparatus. The sheet finishing apparatus receives a sheet having printed matter thereon from the image forming apparatus in order to provide the printed sheet with various post-image-forming processes including jogging, sorting, stapling, punching, etc. Such an apparatus normally has a complex structure with various mechanisms packed into a single body. As a result, such sheet finishing devices are typically ineffective in preventing paper jams and it is typically difficult to remove paper jams therefrom. Several attempts have been made to improve the paper jam handling of such sheet finishing devices.
A published Japanese unexamined patent application, No. 7-187479 (1995), describes an apparatus that automatically ejects any sheet left in a jogger unit to an ejection tray and that unifies several post-image-forming functions such as jogging, stapling, ejection in one unit. The sheet left in the jogger unit, however, is normally not used and therefore it should not be mixed with other sheets in the ejection tray. In addition, the unified processes result in a complex mechanism and an increase in manufacturing costs.
Another published Japanese unexamined patent application, No. 10-129921 (1998), describes an apparatus in which an external cover is unified with a drawing unit in order to decrease manufacturing costs of the apparatus. In fact, however, the cost is relatively high in comparison with an apparatus in which the unit does not include a drawing unit.
The present invention provides a novel sheet finishing apparatus that is configured to be connected with an image forming apparatus. In one example, a novel sheet finishing apparatus includes a sheet tray, a pair of jogging fences, and a case. The sheet tray stacks a plurality of sheets that have been sent from an image forming apparatus. The pair of jogging fences holds the sheets stacked in the sheet tray and jog the sheets in a transverse direction relative to a sheet transferring direction. The pair of jogging fences is controlled to move inwards and outwards (i.e. toward and away from each other). The case encloses the apparatus and includes a plate covering the sheet tray from an operator accessible side. The plate has an opening. When the pair of jogging fences are expanded to outward limits, one of the pair of jogging fences at the operator accessible side is brought to pass by the plate through the opening and to locate at a position outside relative to the plate.
When a sheet jam occurs in the sheet tray, the pair of jogging fences is expanded to have a predetermined distance away from each other.
The pair of jogging fences preferably includes a first jogging member for jogging the sheets in a transverse direction relative to the sheet transferring direction and a second jogging member for jogging the sheets in a direction of a sheet thickness. When the pair of jogging fences is expanded to the predetermined distance away from each other, a closest distance between an edge of the second jogging member at a center side of the sheet tray and an edge of the opening of the plate is sufficient for a manual removal of the sheet jammed in the sheet tray.
The present invention further provides a novel sheet finishing apparatus that is configured to be connected to an image forming apparatus. In one example, a novel sheet finishing apparatus includes a sheet tray, a pair of jogging fences, and a controller. The sheet tray stacks a plurality of sheets that have been sent from an image forming apparatus. The pair of jogging fences holds the sheets stacked in the sheet tray and jogs the sheets in a transverse direction relative to a sheet transferring direction. The controller controls the pair of jogging fences to move inwards and outwards. At a power-on time, the controller controls the pair of jogging fences to move a predetermined distance away from each other and to stop for a predetermined time period when a sheet is detected in the pair of jogging fences.
When the pair of jogging fences are moved the predetermined distance away from each other, the pair of jogging fences may be positioned at the home position, or they may be positioned at or close to the most expanded position.
The present invention further provides a novel method of sheet jogging. In one example, a novel method of sheet jogging includes the step of providing a power to a sheet finishing apparatus. The method includes a step of determining whether a sheet remains in a sheet tray for stacking a plurality of sheets that have been sent from an image forming apparatus. The method also includes a step of moving a jogging member a predetermined distance when a sheet is detected in the sheet tray, where the jogging member holds sheets stacked in the sheet tray and jogs the sheets in a transverse direction relative to a sheet transferring direction. The method further includes the step of stopping the jogging member for a predetermined time period.
When the jogging member is moved the predetermined distance, the jogging member may be positioned at the home position, or may be positioned at or close to the most expanded position.